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authorRafael J. Wysocki <rjw@sisk.pl>2006-04-18 22:20:29 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-04-19 09:13:49 -0700
commit4a3b98a422a20dedf3a2a40c44892d6e7e665157 (patch)
tree24387ffda32d2d7a8582116cd39654bf1fac19fe /kernel/power
parent8db08de4f6ae24e90aedf5125b5ddd52ffff15f4 (diff)
[PATCH] swsusp: prevent possible image corruption on resume
The function free_pagedir() used by swsusp for freeing its internal data structures clears the PG_nosave and PG_nosave_free flags for each page being freed. However, during resume PG_nosave_free set means that the page in question is "unsafe" (ie. it will be overwritten in the process of restoring the saved system state from the image), so it should not be used for the image data. Therefore free_pagedir() should not clear PG_nosave_free if it's called during resume (otherwise "unsafe" pages freed by it may be used for storing the image data and the data may get corrupted later on). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/power')
-rw-r--r--kernel/power/snapshot.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index c5863d02c89..3eeedbb13b7 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -240,14 +240,15 @@ static void copy_data_pages(struct pbe *pblist)
* free_pagedir - free pages allocated with alloc_pagedir()
*/
-static void free_pagedir(struct pbe *pblist)
+static void free_pagedir(struct pbe *pblist, int clear_nosave_free)
{
struct pbe *pbe;
while (pblist) {
pbe = (pblist + PB_PAGE_SKIP)->next;
ClearPageNosave(virt_to_page(pblist));
- ClearPageNosaveFree(virt_to_page(pblist));
+ if (clear_nosave_free)
+ ClearPageNosaveFree(virt_to_page(pblist));
free_page((unsigned long)pblist);
pblist = pbe;
}
@@ -389,7 +390,7 @@ struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask, int safe_needed
pbe->next = alloc_image_page(gfp_mask, safe_needed);
}
if (!pbe) { /* get_zeroed_page() failed */
- free_pagedir(pblist);
+ free_pagedir(pblist, 1);
pblist = NULL;
} else
create_pbe_list(pblist, nr_pages);
@@ -736,7 +737,7 @@ static int create_image(struct snapshot_handle *handle)
pblist = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 1);
if (pblist)
copy_page_backup_list(pblist, p);
- free_pagedir(p);
+ free_pagedir(p, 0);
if (!pblist)
error = -ENOMEM;
}